PC to ATmega16 Communication with LED Display

Several devices collect data from sensors and other input devices and these data needs to be sent to another devices, like a computer, for further processing. Data communication between two devices is generally done in two ways: parallel and serial. In the parallel communication, data transfer is fast and uses more number of signal lines. This mode is good for short range data transfer. Serial communication on the other hand, uses only one or two data lines to transfer data and is generally used for long distance communication.

There are many ways to interface microcontroller to computer; the easiest way is through serial port of computer. But the current generation PCs and Laptops do not have Serial Ports in them. So, we will use a USB to Serial Cable with computer. A USB to Serial Cable creates a virtual serial port in the computer. The communication between a PC and a microcontroller through serial port can be achieved by using USART protocol in asynchronous mode, MAX232 and a terminal software. USART is a full duplex communication protocol used to transfer data between two device serially, MAX232 is a level converter which converts the CMOS logic levels from microcontroller into RS232 logic levels of computer and vice versa. And the terminal software is used to send data from computer and to see received data in computer.

In this project, we will learn How to interface a PC with AVR ATmega16 microcontroller and How to send data from computer to microcontroller. Here, data from the computer will be sent to ATmega16 microcontroller through the RealTerm terminal software. We will press different keys from the computer keyboard and the RealTerm terminal software will send the ASCII value of the each pressed keys to the microcontroller through the serial port of computer. The microcontroller will receive each data sent by computer and it will display it in the 1×8 LED array. The above process continues forever.